Yes, but not in the sense you suggest. Ironically to save costs for the consumers, and improve reliability. Making the system suitable for safe updates without proper disconnecting and partial disassembly and tolerant to untrustad (also in electrical not only in software sense) peripherials would have added a lot to the piecewise cost. (think: more I/O protection electronics, more testing of upgradeability testing with untrusted tools with many failure modes, durable upgrade connectors fitting the size and other constraints).

Still no user could and should upgrade that software, as any complication or untrusted software would be a safety hazard, and lengthy official regulatory evaluation and approval process is needed needed for every new version. (think: Road Permission Level revalidation may be needed (overseen by authorities) to allow a firmware to take part in traffic)

The repair shops can save lots of cost compared to end users, as these tools are not cheap, but compatible with most manufacturers, so are needed anyway.